JP2800224B2 - Electrophotographic photoreceptor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electrophotographic photoreceptor having high sensitivity and excellent characteristics from a visible light region to a near infrared wavelength region.

[Conventional technology and its problems]

2. Description of the Related Art Conventionally, photoconductive materials such as selenium, cadmium sulfide, and zinc oxide have been widely used for a photosensitive layer of an electrophotographic photosensitive member.

Studies have been made on the use of an organic photoconductive substance represented by polyvinyl carbazole for a photosensitive layer of an electrophotographic photosensitive member, and some of them have been put to practical use.

Organic photoconductive materials are lighter than inorganic materials, are easier to form films, are easier to manufacture photoconductors,
The material has advantages such as harmlessness.

In recent years, laser beam printers (LBPs), which use laser light as a light source instead of conventional white light and have the advantages of high speed, high image quality, and low impact, have become widespread in conjunction with advances in information processing systems. There is a demand for the development of a material that can meet the demand.

In particular, among laser beams, in recent years, semiconductor lasers, which have been increasingly applied to compact disks, optical disks, and the like and have remarkable technological progress, have been actively applied in the field of printers as compact and highly reliable light source materials.

In this case, since the wavelength of the light source is around 800 nm, 800 nm
There is a strong demand for the development of a photoreceptor having high sensitivity to long wavelength light before and after.

JP-A-59-49544, 5
9-214034, 61-109056, 61-171771, 61-21705
No. 0, 61-239248, 62-67094, 62-133461, 62-
275272, 63-198067, 63-198068, 63-210942
And 63-218768, and various oxytitanium phthalocyanines each having a suitable crystal type as a material for an electrophotographic photosensitive member are known. However, there has been a demand for an electrophotographic photoreceptor that has higher sensitivity to long-wavelength light and good other electrical characteristics.

The present inventors have conducted intensive studies on an electrophotographic photosensitive member using oxytitanium phthalocyanines, and found that the X-ray diffraction spectrum showed a Bragg angle (2θ ± 0.2 °) of 27.
When a photoreceptor is prepared using oxytitanium phthalocyanine as a charge generating material and a specific hydrazone as a charge transporting material, which exhibits a main clear diffraction peak at 3 °, the desired purpose is achieved to achieve the desired chargeability, sensitivity, and darkness. The present inventors have found that it is possible to provide a photoconductor for electrophotography in which attenuation, residual electrification, and the like are well-balanced, and have completed the present invention.

[Means for solving the problem]

That is, the gist of the present invention is to provide an electrophotographic photoreceptor having a photosensitive layer containing a charge generating material and a charge transporting material on a conductive support, and as a charge generating material, a Bragg angle (X-ray diffraction spectrum). 2θ ± 0.2 °) Oxytitanium phthalocyanine showing a main diffraction peak at 27.3 ° is used, and the following general formula [I] is used as a charge transporting material. (Wherein R ¹ and R ² may be the same or different from each other;
Each represents a hydrogen atom, an alkyl group, an aralkyl group, an allyl group or an aryl group, further R ¹ and alkylene residue or R ¹ and R ² form a heterocyclic ring of five-membered ring or six-membered ring and R ² Either one or both of them may independently represent an alkylene residue forming a 5-membered or 6-membered heterocyclic ring with the A ring. R ³ represents a hydrogen atom, a lower alkyl group, a lower alkoxy group, a halogen atom, a nitro group or a disubstituted amino group, R ⁴ represents a lower alkyl group,
Allyl group, phenyl group, substituted phenyl group, naphthyl group,
Alternatively, it may represent an aralkyl group, and R ⁴ and B may form a 5- or 6-membered heterocyclic ring. R ⁵ is a hydrogen atom,
Represents a lower alkyl group, a lower alkoxy group, an alkylamino group or an acylamino group. The present invention relates to an electrophotographic photoreceptor characterized by using a hydrazone represented by the formula:

(Operation) Hereinafter, the present invention will be described in detail.

Oxytitanium phthalocyanine used as a charge generating material among the materials forming the electrophotographic photosensitive agent of the present invention has a main diffraction peak at 27.3 ° at a Bragg angle (2θ ± 0.2 °) in its X-ray diffraction spectrum. In the present invention, “main diffraction peak” refers to the X
It refers to the strongest (highest) peak in the line diffraction spectrum.

Oxytitanium phthalocyanine powder X used
Examples of the line spectrum are shown in FIGS. As shown
The main peak is the diffraction peak at a Bragg angle (2θ ± 0.2 °) of 27.3 °. Other than the peak, various fluctuations occur depending on detailed conditions. ) Is preferably 50% or less as a photoreceptor for electrophotography in terms of chargeability, sensitivity and the like.

The method for producing oxytitanium phthalocyanine used in the present invention is not particularly limited, but is produced, for example, by the following method.

A method for producing type [II] crystals described in Production Example 1 of JP-A-62-67094. That is, orthophthalodinitrile and a halide of titanium are heated and reacted in an inert organic solvent, and then hydrolyzed.

Direct Various crystal forms of oxytitanium phthalocyanine, an organic acid solvent, sulfuric acid or the formula R-SO ₃ H (represented in the formula, R may have a substituent, an aliphatic or aromatic residue.) Or heat treatment with a mixed solvent of a water-insoluble organic solvent and water in some cases.

If desired, previously dissolved in concentrated sulfuric acid and then released into ice water, or made amorphous by a known method such as a mechanical grinding method such as a paint shaker, a ball mill, or a sand gran Indian mill, and then heat-treated with the above sulfonated product. Heat treatment is performed with a mixed solvent of a water-insoluble organic solvent and water.

In the case of the above-mentioned treatment with a sulfonated product, it can also be produced by employing a mechanical grinding method such as a paint shaker, a ball mill, and a sand grind mill instead of the heat treatment.

As the charge transport material, a compound represented by the general formula [I] is used. Wherein R ¹ and R ² are a hydrogen atom; a methyl group, an ethyl group,
Alkyl group such as propyl group; aralkyl group such as benzyl group and phenethyl group; aryl group such as allyl group or phenyl group, naphthyl group, substituted phenyl group and substituted naphthyl group. These may be the same or different from each other.

Further, R ¹ and R ^{2 represent} a pyrrolidine residue or a piperidine residue, or one or both of R ¹ and R ² independently form a 5-membered or 6-membered heterocyclic ring with the A ring. May represent an alkylene residue.

R ³ is a hydrogen atom; a lower alkyl group such as a methyl group and an ethyl group; a lower alkoxy group such as a methoxy group, an ethoxy group and a propoxy group; a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom and an iodine atom; R ⁴ represents a lower alkyl group such as a methyl group, an ethyl group, a propyl group, or a butyl group; an allyl group; a phenyl group; a methylphenyl group or a methoxyphenyl group And a substituted phenyl group such as chlorophenyl group; a naphthyl group or an aralkyl group such as benzyl group or phenethyl group.

And R ⁴ and B are a 5-membered or 6-membered heterocyclic ring, for example, May be formed.

R ⁵ is a hydrogen atom; a lower alkyl group such as a methyl group or an ethyl group; a lower alkoxy group such as a methoxy group or an ethoxy group;
An alkylamino group such as a dimethylamino group and a diethylamino group; and an acylamino group such as an acetylamino group or a benzoylamino group.

The photoreceptor of the present invention will be described in more detail. The photoreceptor of the present invention contains a charge generation material and a charge transport material on a conductive support. Specifically, usually, the charge generation material is directly deposited or coated as a dispersion with a binder to form a charge generation layer, and then the charge transport is performed by casting from an organic solvent solution and dissolving / dispersing the binder with the binder. Although the laminated photoreceptor is formed by forming a charge transport layer containing a material, the charge generating layer and the charge transport layer may be laminated in the reverse order.

Further, a single-layer type photoreceptor in which a charge generating material and a charge transporting material are dispersed and dissolved in a binder and coated on a conductive support may be used.

In addition to these, an intermediate layer such as an adhesive layer and a blocking layer, and a layer for improving electric characteristics and mechanical characteristics such as a protective layer may be provided.

As the conductive support, any of those used in known electrophotographic photoreceptors can be used. Specific examples include metal drums and sheets of aluminum, stainless steel, copper, and the like, and laminates and vapor-deposits of these metal foils. Further, a plastic film, a plastic drum, paper, a paper tube, and the like, which are subjected to a conductive treatment by applying a conductive substance such as metal powder, carbon black, copper iodide, and a polymer electrolyte together with an appropriate binder, may be mentioned. Further, a plastic sheet or drum containing a conductive substance such as a metal powder, carbon black, or carbon fiber to become conductive may be used.

Further, plastic films and belts which have been subjected to conductive treatment with a conductive metal oxide such as tin oxide or indium oxide may be used. The charge generation layer formed on these conductive supports is formed by dissolving or dispersing the oxytitanium phthalocyanine particles of the present invention and the binder polymer and, if necessary, the organic photoconductive compound, the dye, and the electron-withdrawing compound in a solvent. The obtained coating liquid is obtained by coating and drying. Examples of the binder include polymers and copolymers of vinyl compounds such as styrene, vinyl acetate, vinyl chloride, acrylate, methacrylate, vinyl alcohol, and ethyl vinyl ether, polyvinyl acetal, polycarbonate, polyester, polyamide, polyurethane, and cellulose ester. , Cellulose ether, phenoxy resin, silicon resin, epoxy resin and the like. The ratio of oxytitanium phthalocyanine to binder polymer is not particularly limited, but generally, 5 to 500 parts by weight, preferably 20 to 300 parts by weight, of binder polymer is used per 100 parts by weight of oxytitanium phthalocyanine.

The thickness of the charge generation layer is 0.05 to 5 μm, preferably 0.1 to 5 μm.
２2 μm.

The charge transport layer into which charge carriers are injected from the charge generation layer contains a charge transport material having high carrier injection efficiency and transfer efficiency.

A binder polymer is used for the charge transport layer as needed. As the binder polymer, a polymer that has good compatibility with the above-described charge transporting material, and does not crystallize or charge-separate the charge transporting material after forming the coating film, is preferable.
Examples thereof include polymers and copolymers of vinyl compounds such as styrene, vinyl acetate, vinyl chloride, acrylates, methacrylates, butadiene, polyvinyl acetal, polycarbonate, polyester,
Examples thereof include polysulfone, polyphenylene oxide, polyurethane, cellulose ester, cellulose ether, phenoxy resin, silicon resin, and epoxy resin.
The amount of binder polymer used is usually 100
It is in the range of 50-3000 parts by weight, preferably 70-1000 parts by weight, based on parts by weight. In addition to the above, various additives for improving the mechanical strength and durability of the coating film can be used in the charge transport layer.

Examples of such additives include well-known plasticizers, various stabilizers, fluidity-imparting agents, and cross-linking agents.

〔The invention's effect〕

The electrophotographic photoreceptor of the present invention obtained in this manner has high sensitivity, low residual potential, high chargeability, and small fluctuation due to repetition, and particularly, good charge stability which affects image density. Therefore, it can be used as a highly durable photoconductor. Also, since the sensitivity is high in the region of 750 to 850 nm, it is particularly suitable for a photoreceptor for a semiconductor laser printer.

〔Example〕

Hereinafter, the present invention will be described more specifically with reference to Production Examples and Examples.

Production Example 1 97.5 g of phthalodinitrile was added to 750 ml of α-chloronaphthalene
Then, under a nitrogen atmosphere, 22 ml of titanium tetrachloride was added dropwise. After dropping, the temperature was raised, and the mixture was reacted at 200 to 220 ° C. for 3 hours with stirring, then allowed to cool, and heated at 100 to 130 ° C. for 100 hours.
Washed with 200 ml of α-chloronaphthalene heated to ℃.
The resulting crude cake was washed with 300 ml of α-chloronaphthalene and then with 300 ml of methanol at room temperature, and further washed with 800 ml of methanol for 1 hour under hot water, and the resulting cake was suspended in 700 ml of water. The mixture was turbid and washed with hot washing for 2 hours.

The pH of the solution was 1 or less. PH of the solution is 6
Repeated until ~ 7.

FIG. 1 shows an X-ray diffraction spectrum of the obtained oxytitanium phthalocyanine.

As is clear from FIG. 1, the Bragg angle (2θ ± 0.2
In (ii), a sharp peak is shown at 27.3 °, but the other peaks are relatively broad peaks.

Production Example 2 40 g of β-type oxytitanium phthalocyanine having an X-ray diffraction spectrum shown in FIG. 3 was dissolved in 400 ml of 98% concentrated sulfuric acid, and stirred in an ice bath for 3 hours.

Then, a concentrated sulfuric acid solution was dropped into 1.6 parts of ice water over 30 minutes to make the mixture sufficiently uniform, and then passed. The resulting precipitate is neutralized by suspending and washing with an aqueous solution of sodium acetate and then neutralized by suspending and washing with water.
110 g were obtained.

Further, 85 g of the obtained wet cake was suspended in 770 ml of water, 57 ml of ortho-dichlorobenzene was added, and the mixture was stirred at a temperature of 60 ° C. for 1 hour. The reaction solution was decanted to remove most of the water-ortho-dichlorobenzene, then 800 ml of methanol was added, and the mixture was stirred at a temperature of 60 ° C. for 2 hours, then filtered and dried by a conventional method to obtain 18 g of blue oxytitanium phthalocyanine. Obtained.

FIG. 2 shows an X-ray diffraction spectrum of the obtained oxytitanium phthalocyanine.

The peak in the X-ray diffraction spectrum of oxytitanium phthalocyanine obtained as evident from FIG.
1 shows a sharp peak at a Bragg angle (2θ ± 0.2 °) of 27.3 °, but the other peaks are relatively broad peaks.

Example 1 Oxytitanium phthalocyanine produced in Production Example 1
0.4 g of polyvinyl butyral 0.2 g of 4-methoxy-4-
Disperse with a sand grinder together with 30 g of methyl-2-pentanone, apply this dispersion on an aluminum vapor-deposited layer vapor-deposited on a polyester film using a film applicator to a dry film thickness of 0.3 g / m ² and dry. Thus, a charge generation layer was formed.

On this charge generating layer, 90 parts of 4-N, N-diethylamino-cinnamaldehyde diphenylhydrazone and a polycarbonate resin (Iupilon E-200, manufactured by Mitsubishi Gas Chemical Company, Inc.)
0) A charge transport layer of 100 parts having a thickness of 17 μm was laminated to obtain an electrophotographic photosensitive member having a laminated photosensitive layer.

The half-life exposure (E1 / 2) was measured as the sensitivity of the photoreceptor using an electrostatic copying paper tester (Model SP-428 manufactured by Kawaguchi Electric Works). That is, the photoconductor is negatively charged by corona discharge with an applied voltage set so that the corona current becomes 50 μA in a dark place, and then 775 n having an intensity of 0.125 μW / cm ^2.
Exposure with monochromatic light of m, surface potential from -500V to -250V
Exposure (E 1/2) required to halve the value
It was 0.17 μJ / cm ² .

Example 2 A photoreceptor was prepared in the same manner as in Example 1 except that hydrazones shown in the following table were used in place of 4-N, N-diethylamino-cinnamaldehyde diphenylhydrazone used in Example 1 below. The sensitivity was measured in the same manner as in Example 1.

 The results are summarized in the table below.

Comparative Example A photoconductor was prepared in the same manner as in Example 1, except that N-methyl-carbazole-3-aldehyde-diphenylhydrazone was used instead of 4-N, N-diethylamino-cinnamaldehydediphenylhydrazone. Then, the half-exposure amount at 775 nm light was measured in accordance with Example 1 and found to be 0.34 μJ / cm ² .

[Brief description of the drawings]

1 and 2 are X-ray diffraction spectra of oxytitanium phthalocyanine used in the present invention. FIG.
6 is an X-ray diffraction spectrum of β-type oxytitanium phthalocyanine used in Production Example 2.

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-2-136862 (JP, A) JP-A-64-82045 (JP, A) JP-A-62-75473 (JP, A) JP-A 64-64 17066 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03G 5/06 372 G03G 5/06 321

Claims (1)

(57) [Claims] 1. An electrophotographic photosensitive member having a photosensitive layer containing a charge generating material and a charge transporting material on a conductive support, the charge generating material having a Bragg angle (2θ ± 2) in its X-ray diffraction spectrum. 0.2 ゜) Oxytitanium phthalocyanine showing a main diffraction peak at 27.3 ゜ is used, and the charge transporting material is represented by the following general formula [I] (Wherein R ¹ and R ² may be the same or different from each other;
Each represents a hydrogen atom, an alkyl group, an aralkyl group, an allyl group or an aryl group; furthermore, R ¹ and R ² together form an alkylene residue or a R ¹ and R ² which form a 5- or 6-membered heterocyclic ring; Either one or both may independently represent an alkylene residue which forms a 5-membered or 6-membered heterocyclic ring with the A ring. R ³ represents a hydrogen atom, a lower alkyl group, a lower alkoxy group, a halogen atom, a nitro group or a disubstituted amino group, and R ⁴ represents a lower alkyl group, an allyl group, a phenyl group, a substituted phenyl group, a naphthyl group, or an aralkyl group. R ⁴ and the B ring may form a 5- or 6-membered heterocyclic ring. R ⁵ represents a hydrogen atom, a lower alkyl group, a lower alkoxy group, an alkylamino group or an acylamino group. A photoreceptor for electrophotography, comprising using a hydrazone represented by the formula: